Abstract. The proposed influence of cosmic rays on cloud formation is tested
for the effect of sudden intensity changes of CR (Forbush
decreases) on cloudiness. An attempt is made to widen the investigated
period covered by satellite observation of cloudiness. As an
indicator of cloud cover, the diurnal temperature range (DTR - a
quantity anticorrelated with cloudiness) is used. The superposed
epoch analysis on a set of isolated Forbush decreases is conducted
and the results for a region of Europe are presented. The effect
of Forbush decrease on DTR is statistically significant only if
the analysis is restricted to high amplitude FDs (above the
threshold value of 7% with the respect to undisturbed CR
intensity). The magnitude of the effect on DTR is estimated to be
(0.38 ± 0.06) °C.